Electrical contact assembly

ABSTRACT

The assembly comprises a plurality of aligned pairs of spaced apart contact fingers directly attached at one end on opposite sides of a conductive bar without the use of intermediate connectors or alignment frames. The contact fingers of adjacent pairs are biased toward each other intermediate of their ends by a tension spring disposed between the pairs and secured to a pair of connecting links each having outwardly extending pins overlying the outer surfaces of adjacent fingers. The free ends of the contact fingers are convex toward each other and the convex portions of each pair of contact fingers are arranged to grip directly on opposite sides of a second conductive bar.

United States Patent Leonard [45] Mar. 27, 1973 [54] ELECTRICAL CONTACTASSEMBLY [75] Inventor: James H. Leonard, Cedar Rapids,

Iowa

[73] Assignee: square l Company, Parli liidge, 111. 22 Filed: Nov. 18,1971 [21] Appl. No.: 200,249

Related us. Application Data [63] Continuation of Ser. No. 58,906, July28, 1970,

2,303,425 12/1942 Bickham ..339/64R FOREIGN PATENTSHQR APPLICATlONS10,145 11/1932 Australia ..339/255 P 1,378,069 10/1964 France....339/255 P 187,863 10/1966 U.S.S.R ..339/255 P PrimaryExaminer-Joseph H. McGlynn Attorney-l-1arold J. Rathbun et al.

[57] ABSTRACT The-assembly comprises a plurality of aligned pairs ofspaced apart contact fingers directly attached at one end on oppositesides of a conductive bar without the use of intermediate connectors oralignment frames. The contact fingers of adjacent pairs are biasedtoward each other intermediate of their ends by a tension springdisposed between the pairs and secured to a pair of connecting linkseach having outwardly extending pins overlying the outer surfaces ofadjacent fingers. The free ends of the contact fingers are convex towardeach other and the convex portions of each pair of contact fingers arearranged to grip directly on opposite sides of a second conductive bar.

9 Claims, 3 Drawing Figures Patented March 27, 1973 3,723,940

INVENTOR. JAMES H. LEONARD 20M 9, wad...

ELECTRICAL CONTACT ASSEMBLY This application is ajcontinuation of Ser.No. 58,906, filed July 28, 1970, and now abandoned.

SUMMARY OF THE INVENTION The present invention relates to adisconnecting contact assembly for electrical apparatus. Prior artcontact devices of this general type are excessively complex inconstruction, generally using two compression springs per pair offingers with complicated spring holders. The contact fingers are usuallyattached to an intermediate holder which is in turn attached to theconductive bar. To avoid these limitations, prior art devices have to beprovided with specially grooved conductive bars or with frames forstructural support and alignment.

The present invention overcomes these disadvantages by providing contactfingers directly secured at one end on opposite sides of a conductivebar. The fingers are biased toward each other by tension springs securedbetween and acting upon adjacent pairs of contact fingers. The contactfingers are arranged to have rocking surfaces on the conductive bar andthe spring holders are simple metal stampings each with a pin extendingthrough it. Only one spring is required for two pairs of contactfingers.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of aconnector made in accordance with this invention;

FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along the line 33 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, acontact assembly in accordance with this invention comprises a pluralityof spaced pairs of contact fingers I 1. The upper and lower contactfingers 11 may be identically formed from substantially flat pieces ofconducting material so that each has a bowed portion 12 and a similarlybowed portion 14. An intermediate planar portion 15 of each contactfinger 11 may be provided with a transverse notch or indentation 16, andan end portion 17 of each, cutwardly of its bowed portion 14, has anaperture 19 extending therethrough.

A movable conductive bar 20 is provided with a plurality of apertures 21aligned in spaced apart relationship along, and a uniform distance from,an outer edge face 22vof the conductive bar 20. A pair of the fingers 11is affixed on the conductive bar 20 at each aperture 21, one contactfinger 11 being positioned on each side of the conductive bar 20 withthe convex side of the bowed portions 12 and 14 directed inwardly andthe apertures 19 aligned with the aperture 21 as shown in FIG. 2.Securing means such as a bolt 24 may be in serted respectively throughthe aligned apertures 19 and 21 and secured by a releasable fastenerssuch as a nut 25.

Adjacent pairs of the contact fingers 11 are biased inwardly by atension spring assembly including a tension spring 26 and a pair ofidentical spring links 27. Each spring link 27 is a flat, substantiallyrectangular plate and is provided with grooves 29 in its opposite sideedges near one end forthreaded securement to an end portion of itsassociated tension spring 26. An aperture 30 is punched near the otherend of each of the links 27 to receive a bias pin 31. Each bias pin 31is preferably of a length equal to the distance across a mounted spacedpair of the contact fingers l1 and has a central portion 33 ofdiminished cross section. Each bias pin 31 is fitted into its associatedaperture 30 until the central portion 33 is loosely held within theaperture 30. Tensioning of the spring 26 between adjacent pairs ofcontact fingers 11 locks the central portion 33 within the aperture 30and prevents longitudinal motion of the bias pin 31. 1

Each tension spring assembly is held between two adjacent pairs ofcontact fingers 11 by the positioning of the bias pins 31 in theindentations 16 on the intermediate planar portions 15 of the fingers11. The inward surfaces of the bowed portions 14 of the contact fingersl1 abut the conductive bar 20 near the outer edge face 22 and serve asfulcrums for pivotal motion of the contact fingers 11. The inwardbiasing of the tension spring 26 thus causes outward motion of the endportions 17 of the upper and lower contact fingers 11 of each pair whichis limited by abutment with the head of the' bolt 24 and the nut 25,respectively.

The inwardly bowed portions 12 are adapted to grasp a fixed conductivebar 32, such as a bus bar, therebetween. Thus, the distance between thebowed portions 12 of each pair of contact fingers 11 should normally beless than the thickness of the fixed conductive bar 32. This distancecan be selected by adjustment of the bolts 24 and nuts 25.

Insertion of the fixed conductive bar 32 in the contact assembly 10spreads apart the upper and lower contact fingers 11 of each pair at theinwardly bowed portions 12, the contact fingers 11 pivoting on the bowedportions 14 causing inward motion of the end portions 17. The fixedconducting bar 32 is preferably of the same thickness as the movableconducting bar 20. The spread of the bowed portions 12 increases thetension of the spring 26. This force is applied substantially equally tothe bowed portions 12 and the bowed portions 1d and enhances theelectrical contact with the fixed conductive bar 32 and the movableconductive bar 20, respectively.

Open end portions 34 of the contact fingers 11 are flared outwardly tofacilitate insertion of the conductive bar 32. The flared open ends 34and independent action of the contact fingers 11 enable the contactfingers 11 to be fitted in electrical contact on a fixed conductive bar32 when it is not in perfect alignment with the movable conductive bar20. End pins 35 in the movable conductive bar 20 may be provided toprevent any inadvertent rotation of the contact fingers 11 about theaxis oftheir associated bolts 24.

In this manner a disconnecting contact assembly is provided, having asimplified mounting and tension spring assembly. The contact fingersfunction without the use of frames or special alignment apparatus. Itshould be noted that the contact assembly of the present invention issimilarly operable when secured to the fixed conducting bar 32 and usedto grasp the movable conducting bar 20.

Iclaim:

1. A disconnecting contact assembly for effecting an electricalconnection between first and second conductive members upon relativemovement of substantially coplanar, generally flat connecting portionsof the members toward each other, said assembly comprising one of themembers, the connecting portion of said one of the members havingapertures therethrough aligned in a row substantially parallel to andspaced inwardly from an edge thereof, a plurality of laterally spacedpairs of contact fingers aligned in a row along said edge with thefingers having respective outer end portions extending outwardly in thesame direction from said edge, the contact fingers of each pair beingdisposed respectively on opposite sides of the connecting portion ofsaid one member and having respective holes at their inner end portionssubstantially coaxially aligned with a respective one of the apertures,each of the contact fingers having a first contact surface inelectrically conductive engagement with the connecting portion of saidone member and a second contact surface at its outer end portion forelectrically conductive engagement with the connecting portion of saidother member upon movement of the members toward each other, a pluralityof fastening means, each of said fastening means extending through oneof the apertures and the pair of contact finger holes aligned therewith,and tension spring means disposed respectively between adjacent pairs ofthe contact fingers and biasing the contact fingers of each adjacentpair toward each other.

2. A contact assembly as in claim 1 wherein said first contact surfaceis in electrically conductive engagement with the connecting portion ofsaid one member between the row of apertures and said edge.

3. A contact assembly as in claim 1 wherein said fastening means isadjustable for varying the distance between the second contact surfacesof each pair of contact fingers.

4. A contact assembly as in claim 1 wherein said fastening meanscomprises bolts inserted respectively through the pairs of holes at theinner ends of the pairs of contact fingers and through the respectivealigned apertures in said one conductive member and a releasablefastener secured to the bolt.

5. A contact assembly as in claim 1 wherein said edge of said oneconductive member is straight and said pairs of contact fingers arealigned substantially perpendicular to said edge.

6. A contact assembly as in claim 1 wherein the first contact surface ofeach contact finger is a convex surface.

7. A contact assembly as in claim 6 wherein the second contact surfaceof each contact finger is a convex surface.

8. A contact assembly as in claim 1 wherein each tension spring meansincludes a tension spring and a pair of spring links each connected toan opposite end portion of the tension spring and wherein engaging meansextending from the spring links engage the contact fingers of adjacentpairs of contact fingers for biasing the contact fingers of each pairtoward each other.

9. A contact assembly as in claim 8 wherein each of the contact fingershas an outer surface provided with a groove, each spring link has anaperture and said engaging means comprises pin means held in therespective apertures in the spring linlgs, each pin means havmg opposlteend portions received respectively in the grooves of adjacent contactfingers.

k II! t 4

1. A disconnecting contact assembly for effecting an electricalconnection between first and second conductive members upon relativemovement of substantially coplanar, generally flat connecting portionsof the members toward each other, said assembly comprising one of themembers, the connecting portion of said one of the members havingapertures therethrough aligned in a row substantially parallel to andspaced inwardly from an edge thereof, a plurality of laterally spacedpairs of contact fingers aligned in a row along Said edge with thefingers having respective outer end portions extending outwardly in thesame direction from said edge, the contact fingers of each pair beingdisposed respectively on opposite sides of the connecting portion ofsaid one member and having respective holes at their inner end portionssubstantially coaxially aligned with a respective one of the apertures,each of the contact fingers having a first contact surface inelectrically conductive engagement with the connecting portion of saidone member and a second contact surface at its outer end portion forelectrically conductive engagement with the connecting portion of saidother member upon movement of the members toward each other, a pluralityof fastening means, each of said fastening means extending through oneof the apertures and the pair of contact finger holes aligned therewith,and tension spring means disposed respectively between adjacent pairs ofthe contact fingers and biasing the contact fingers of each adjacentpair toward each other.
 2. A contact assembly as in claim 1 wherein saidfirst contact surface is in electrically conductive engagement with theconnecting portion of said one member between the row of apertures andsaid edge.
 3. A contact assembly as in claim 1 wherein said fasteningmeans is adjustable for varying the distance between the second contactsurfaces of each pair of contact fingers.
 4. A contact assembly as inclaim 1 wherein said fastening means comprises bolts insertedrespectively through the pairs of holes at the inner ends of the pairsof contact fingers and through the respective aligned apertures in saidone conductive member and a releasable fastener secured to the bolt. 5.A contact assembly as in claim 1 wherein said edge of said oneconductive member is straight and said pairs of contact fingers arealigned substantially perpendicular to said edge.
 6. A contact assemblyas in claim 1 wherein the first contact surface of each contact fingeris a convex surface.
 7. A contact assembly as in claim 6 wherein thesecond contact surface of each contact finger is a convex surface.
 8. Acontact assembly as in claim 1 wherein each tension spring meansincludes a tension spring and a pair of spring links each connected toan opposite end portion of the tension spring and wherein engaging meansextending from the spring links engage the contact fingers of adjacentpairs of contact fingers for biasing the contact fingers of each pairtoward each other.
 9. A contact assembly as in claim 8 wherein each ofthe contact fingers has an outer surface provided with a groove, eachspring link has an aperture and said engaging means comprises pin meansheld in the respective apertures in the spring links, each pin meanshaving opposite end portions received respectively in the grooves ofadjacent contact fingers.